Prospective, comparative study of cemented, smooth-surfaced titanium stems and polish-surfaced, stainless steel stems at a minimum follow-up of 10 years.

Abstract

Excellent results have been reported with cemented total hip arthroplasty (THA) using both smooth-surfaced and polished-surfaced stems. However, the superiority of polished-surfaced over smooth-surfaced in cemented THA, or vice versa, is still debated. Forty-six smooth-surfaced, triple-tapered, titanium-alloy stem (Group C) and 46 Exeter stems (Group T) have been fixed consecutively at different periods at our institute and prospectively evaluated clinically and radiologically. The area and location demonstrating cortical hypertrophy (CH) was measured in the serial radiograph and compared. The mean postoperative follow-up period was 12.4 years for group C and 10.8 years for group T. No significant difference of clinical results was found between both groups. CH was observed in 8 hips (18.6%) of group C and in 7 hips (17.1%) of group T (NS). Among the hips in which distribution of CH was observed at the medial side, a significantly low proportion belonged to group C (adjusted standardized residual = - 2.3) and a significantly high proportion belonged to group T (adjusted standardized residual = 2.3). The largest area of CH found in each group was 166.1 mm² in group C and 227.6 mm² in group T (NS). The peak location of CH was 100.4% in group C and 84.3% in group T (p = 0.02). Medium-term results of both stems were excellent. CH was observed medially and proximally in group T and laterally and distally in group C.